Optical device and image reading apparatus

An optical device includes a lens body including plural lenses of which optical axes are arranged alongside each other, and a light shielding body that is disposed with respect to the lens body and shields a part of light passing through the plural lenses, in which the light shielding body has a base that is provided, at a position shifted from the optical axes of the plural lenses, along an arrangement direction in which the plural lenses are arranged, and plural projecting portions that are positioned between the plural lenses and project from the base in an intersection direction intersecting the arrangement direction.